The annual bluegrass weevil (ABW) is an insect that can get very ‘angry’: insecticide resistant that is. Surveys have indicated that resistance in this insect is wide spread. Dealing with insecticide resistant ABW can quickly become a nightmare. The best thing to do, if you still can, is to not get the weevils ‘angry’ in the first place. Once they are resistant, there may be no feasible way of getting them susceptible again. There are no silver bullets out there and none in development.

Annual Bluegrass Weevil Adult

Annual Bluegrass Weevil Larvae

Resistance is Sneaky

I estimate that any golf course that has tried to intensively control ABW for at least 5 years will have some level of insecticide resistance. With intensively I mean multiple applications per year over large proportions of the golf course. Resistance tends to sneak up on people. First there are some small problems here and there that will be excused by ‘missing spots’, ‘timing off’, ‘poor weather conditions’, etc. Unfortunately, the typical reaction is to ratchet up the spraying activity. [Read more…]

Having touble controlling your Annual Bluegrass Weevil (ABW) populations? You’re not alone. Insecticide resistance in ABW is a growing and expanding problem. And because the major resistance mechanism involved, enhanced metabolic detoxification of the insecticide active ingredients, is not very specific, the resistance can be very broad. [Read more…]

With the ongoing ‘heat wave’ forsythia should be in full bloom and overwintered adult annual bluegrass weevil (ABW) should have started their spring migration soon. But no reason to panic. Adult ABW are best controlled when forsythias are half gold:half green, when most of them are on the short-mown turf but have not started laying eggs, yet. And given the reversion to cool weather in the coming week (4/15-18), that will likely not happen until early May in central NJ.

Annual Bluegrass Weevil Adult

Annual Bluegrass Weevil Larvae

[Read more…]

Annual Bluegrass Weevil
Photo: B. McGraw

Adults of the annual bluegrass weevil (ABW) spring generation have started to emerge in significant numbers over the last few days at Rutgers Hortfarm 2 in New Brunswick and at golf courses in North Jersey. Peak densities of new ABW adults should occur throughout the central and northern New Jersey and the NY metropolitan area over the next 1-2 weeks.

These spring-generation adults mate and will start laying eggs quickly. The resulting second generation is present predominantly as large larvae around late July-early August, when additional damage — usually less severe than spring damage — may occur. The second generation pupates in August and starts emerging as adults around mid-August.

Areas where significant adult densities are observed (directly, in clippings, with soap irritant, or by vacuum sampling) in late June-early July may need to be treated. However, overuse of insecticides, particularly of pyrethroids, is likely to lead to the development of pesticide-resistant ABW populations. To avoid this highly undesirable scenario insecticides should be applied only where and when necessary and pyrethroids should be used no more than once per year. [Read more…]